Vandals hopped a fence and dumped at least 4 gallons of paint into a North Valencia HOA pool and more into the hot tub late Wednesday or early Thursday, causing $300,000 to $400,000 in damage.

“This damage is so major we have to rip out our entire pool system,” said Wolfgang Costello, president of the Northbridge Homeowners Association.

Because the paint was pumped through the pool system, it coated and clogged the pipes and damaged two recently purchased, $25,000 boilers, Costello said during a tour of the damage Thursday.

To repair the damage, workers will have to replace all the pipes, replace the new boilers, re-line the pool and rip up concrete 4 feet deep from the pool to the pumps and to the hot tub.

A reward not to exceed $5,000 has been posted by the company managing the pool for Northbridge residents for information leading to the arrest and conviction of any of the culprits.

The vandalism occurred some time between Wednesday night and 6 a.m. Thursday. Blotches of spilled paint near the fence indicated the vandals climbed over it to get to the pools at Fairview Lane and Grandview Drive.

They then dumped at least four 1-gallon cans of blue, red, green and yellow house paint into the pool and a significant amount of green paint into the hot tub.

They also tossed deck chairs into the pool.

The Northbridge complex, which was frequented by 1,200 people, offers residents two satellite pools, but that’s little compensation for the more than 100 young members of the Northbridge Bluefins swim team. The vandalized pool where they train is the only one with racing lanes.

Castillo commiserated with Northbridge youth, nodding in the direction of his own son and daughter.

“They come here every day to swim. They were here yesterday,” he said. “Now their summer is over, and it’s middle of July.”

Because of the high loss value, a detective was assigned to the case, said Costello, a spokeswoman for the homeowners association management company, Ross Morgan & Company, which is offering the $5,000 reward.

If arrests are made and people are convicted, restitution is one of the options available to courts on sentencing.

The damage is “hopefully” covered financially by the company’s insurance policy, said Reina Zuckerman, spokeswoman for Ross Morgan.

“This is huge. In my 20 years doing this, I’ve never had an insurance claim this large,” she said.

“I feel like crying. It’s like they did it to my bedroom.”

If the reward leads to convictions and those convicted are minors, restitution could fall on the backs of their parents, who would be expected to pay for some or all of the damage.

Ross Morgan, which also manages pools for the community of North Park near Northbridge, sent a newsletter to association members advising them: “The community has been experiencing some problems with graffiti throughout the neighborhood and surrounding areas.”

The company advised members in the August 2012 newsletter that the city of Santa Clarita offers reward money of $500 for anyone who provides tips that lead to the “arrest and/or conviction” of graffiti vandals.